> ## Documentation Index
> Fetch the complete documentation index at: https://docs.vumasign.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Test keys and live keys

> What a test key can and cannot do, in all three respects.

This is the most confusing thing about the API for a newcomer, so plainly:

* A `vsk_test_` key emails **only** addresses you have verified on
  [Test recipients](https://app.vumasign.com/settings/test-recipients), plus the members of your
  organisation whose sign-in address has been verified. A send to anybody else is refused — it is
  not silently dropped.
* It is **never billed** and never counts against your plan’s document allowance.
* What it produces is a **watermarked sandbox document** that binds nobody. Nothing signed with a
  test key is legally valid. It is a real sealed PDF — so your verification code has something to
  run against — sealed by a certificate issued for the sandbox and for nothing else, and that
  certificate is what says the document binds no one.
* A `vsk_live_` key is the opposite of all three. The two are separate credentials; the
  environment is inside the hashed value, so a test secret cannot be re-presented under a live
  prefix.